BGE: Is there a way to stop my character moving?
You simply need a timer of some sort that must be at a certain value before another attack can be performed. I like using an integer property and adding to it, rather than a timer property because it gives me more control. 
Basics of the system require a property sensor to sense if enough time has passed yet; a property to time; an actuator in incrementally add to the timer (only if not using timer type property) and an actuator to set the property to zero whenever you do attack. The system pictured below also has a cap, so the property doesn't go to high, although it really doesn't matter. 



you may have to click the image to see it closer. :)